The use of poly(oxyalkylene) colorants in thermoplastic resins is known and may be found 10 in the following U.S. Pat. Nos.: 4,978,362 to Kluger et al., 4,812,141 to Baumgartner et al., 4,732,570 to Baumgartner et al., and 4,640,690 to Baumgartner et al. The prior art also shows that poly(oxyalkylene) colorants with higher percentages of the more hydrophlic oxyethylene groups in the polymer chain show reduced extraction levels compared to similar chromophores with high percentages of the more hydrophobic oxypropylene groups. While the colorants with high percentages of oxyethylene groups in the polymer chain show reduced extraction levels, they exhibit lower thermal stability, decreased clarity, and increased difficulty in manufacturing than colorants predominantly substituted with oxypropylene groups. In addition, the prior art references neither teach nor fairly suggest the use of disazo colorants with high percentages of oxypropylene groups, either alone or in random or block copolymers with other poly(oxyalkylene) species, in the polymer side chains for the in situ coloration of thermoplastic resins for reduced extraction, improved clarity, and better stability.